1. Technical Field
The present invention relates to a laser machining method, a laser machining apparatus, and a laser machining program, more specifically, relates to a laser machining method and a laser machining apparatus for setting an optimum machining route for drilling a plurality of holes in a substrate by irradiation with a laser beam, and relates to a laser machining program executed by this laser machining apparatus.
2. Related Art
Examples of such techniques are found in JP-A-2001-195112 (hereinafter referred to as Patent Document 1) and JP-A-2008-049398 (hereinafter referred to as Patent Document 2). In Patent Document 1, a laser drilling route determination method for shortening computation time that is required for route determination is proposed as follows: This laser drilling route determination method applies an algorithm for the traveling salesman problem to determine a route specifying an order of positions to be drilled with a laser beam based on information of a plurality of drilling positions which are set up in advance. In this technique, a route determination based on an algorithm for the traveling salesman problem includes: dividing a machining region including positions to be drilled with a laser beam into a plurality of buckets, determining a traveling route visiting each of the plurality of divided buckets, determining a start extremity and an end extremity in each divided bucket, and determining an optimum route visiting positions to be drilled with the laser beam from the start extremity to the end extremity in each divided bucket. The start extremity is set to the starting point of laser beam irradiation in each divided bucket, and the end extremity is set to the end point of the laser beam irradiation. The end extremity in one bucket is associated with the start extremity in the next bucket to travel.
On the other hand, in Patent Document 2, a laser drilling method is proposed as follows: This laser drilling method can reduce generation of wavelike deformation and the like even in the case where a sheet-shaped member with a low heat resistance is drilled at a narrow pitch. This technique is a method for drill machining by sequential irradiation with a laser beam to a plurality of positions to be drilled in a sheet-shaped member. In at least a part of the plurality of positions to be drilled, one position to be drilled is irradiated with a laser beam, and then another position to be drilled is irradiated with the laser beam if the latter position is out of a predetermined range of distance from the former position, but the latter position is skipped if the latter position is within the predetermined range and then still another position out of the predetermined range is irradiated with the laser beam.